Hi Bunnylady,
I suspect what you have here is an active infection of a protozoan called E Cuniculi. It is quite common and is present in nearly all rabbits although it is usually controlled by the immune system It is a very misunderstood issue. Usually the first clinical signs of an active infection is a "lazy leg". One rear leg, most likely the left, will drag or the rabbit will stumble every once in a while. The neurological deficiencies will increase and the rabbit may start falling on it's side. As the rabbit's immune system mounts a counter attack, there may seem to be resolution....but EC will overwhelm the immune system. It is a wasting disease. You might also see some urinary incontenance as the spores of the protozoa are shed and exit the body with the urine. It might be quite concentrated and smelly. The final battle in this disease is fought in the kidneys and most likely, in the end, the rabbit will be lost to renal system failure.
Now, what I am going to say here....I need you to understand that I am not a doctor. I treat very sick rabbits (and EC is something near and "dear" to me...see our blog) and have the support of some of the best vets in the country. All of my vets are avian/exotics teaching professors and our "special needs" critters are used to train vet students. The only way to truly confirm an active EC infection is post mortem....a necropsy. That is not a desirable event. There is a titer, or blood test, that can be performed....there are only a couple of labs in the US capable of working this lab. The results are open to interpretation. The best view of what is going on is by doing a series of titers over a period of several weeks and observe the rising or falling antibodies. But even this leaves a lot to be desired. We usually treat based on symptoms. Couple of things in your post that concerns me. First, EC does not directly cause head tilt/wry neck....that is a common misconception. Researchers now think, and our experiences here with EC rabbits, show that most of these issues aresecondary infections thatareallowed by the compromised immune system. Our rabbits that have had EC have had an ongoing series of bacterial infections....the ear most often since it is the weakest of the group but also urinary, ocular (eye) issuesand upper respiratory issues have also been seen. The best chance for recovery is actually the rabbit's own immune system. Current treatment is usually based on fenbendazole (panacur) for at least 28 consecutive days....we run at least 60. There is promise with a horse drug that treats EPM in horses....it's a similar infection. That drug is Ponazuril (Marquis). Support of the renal system is essential....maintaining hydration by whatever means....we do a lot of sub-q fluids. Do everything possible to support the immune system....keep things as stress free as possible. I am concerned with using a steroid in this situation....but at one time it was the treatment of choice. But it tends to do the opposite of what needs to happen...it suppresses the immune system. The idea is to boost the immune system not only to fight the EC but to help prevent any secondary bacterial or viral infections. Your rabbit probably feels terrible since the kidneys don't function properly when damaged by EC...and that is where hydration support is essential. I would be comfortable with a little shot of B Comp for a "kick in the powderpuff" that might stimulate the appetite without the side effects. EC can cause problems anywhere in the body....the most common we have seen are hind quarter neurological deficiencies, cataracts/debris in the iris and kidney issues. Head tilt, unless there is obvious head trauma, is usually caused by infections in the middle and/or inner ear and may not be easily observed. We normally culture any debris in the ear and monitor bodytemp. If nothing grows in the petri dish and we have an elevated body temp....most likely the tilt is caused by a pasteurella infection (a bacteria that is sometimes difficult to grow in a culture).
This is a challenging issue to treat and it is very misunderstood. Honestly, very few vets have ever seen a real case of EC...not so much because it is rare but there have never been a lot of rabbit vets around. And most of the EC rabbits are usually euthanized early on. But this monster can be tamed....and we know of rabbits that have gone into a type of remission. Our Yoda (see our blog again) fought a brave batttle and lived a good life for a couple of years after onset of his EC. Only in his last days did his quality of life suffer and it was due torenal failure. I have lots of information on this issue and have had several buns in our rescue with this condition. If you need more info....just PM me. And again, the info I gave you is not a professional opinion...just some thoughts from my experience that you can discuss with your vet. Best wishes.
Randy